Planoqraph co



W- AITKEN. SYSTEM OF MULTIPLING TRUNK WIRES. APPLICATION FILED MAR. 20; 1911.

1,31 1,432, Patented July 29, 1919. 2 J V '4EETS-SHEET l.

THE COLUMBIA PLANOGRAPH c0., WASHINGTON. D.. C,

w. AITKEN. SYSTEM OF MULTIPLING'TRUNK WIRES. APPLICATION FILED MAR. 20. 1917.

l ,3 1 1 A32. Patented July 29, 1919.

4 SHEETS-SHEET 2.

THE COLUMBIA PLANOGRAPM co., WASHINGTON, D. C.

W. AITKEN.

SYSTEM OF MULTIPLING TRUNK WIRES.

APPLICATION HLED MAR. 20, 1911.

- 4 SHEETS-SHEET 3.

Patented July 29 will be best realized if a group of lines WILLIAM AITKEN, or LONDON, ENGL ivn, AssIGiIoR T0 THE REL Y AUTOMATIC} a TELEPHONE coma wpnnvnrnn, on-rolvnon, nivena vn S YSTlElM dr'MUL'rIPLINe TRUNK-WIRES.

To all 10 hom it may concern: 1

Be it known thatl, WILLIAM'AI KEN, a subject of the King of Great-Britain, and resident of Marconi HOuseLStrandiLondon, England, have. invented a new and iiseful System 'of Munipn gf Trunk-Wire's, of which the following is specificationif This invention relates to; a'fmethod" of multipling 'trunlror juncti'on'lines and the switches or over; relays so like'over banks of as to increase'the access fromincoming'lines,

and it is particularly inatic' and semi-automatic telephone systems. The invention will be described more-par'-= ticularly thelike, and maybe associated 'wit'ih jacks on semi-automaticsystemsi 5 Y In theusual way a number of trunks sulficient to carry the traflicis Inultipled over the banks of switches or 'contacts'bf relays appertaining to a group of incoming lines; for .example,ten' trunks to'one hundred subscribers. a i In a relay system each subscribers line would be equipped with ten relays, or a combination of relays to give access to ten 'lines, and subsidiary means would cause a calling line to select and connect with an" idle linefi The object of the inventionis toflreduce the number of bank contacts or relaysneeessary to obtain the required access; or 't0 en-' able groups of switches having a "given number of terminals in a bank to have access to a greater number of lines. This invention is particularly applicable in the case of? ex changes having groups of lines ofmore than two hundred in number. It'is-also, however, applicable to cases in which there are'fewer lines than two hundred in a group, butthe benefits to be derived from it in these cases of smaller-groups are notsogreat as iinthe case of larger groups because they-'may be partially attained by other'means. i :1

The benefits accruing from theinvention be considered. 1

At the pre-digi or line switch stage, it is usual to divide sucha group into sub-groups of 100 lines each having access to 10trun'ks, a total of 100 trunks. If lOOO subscribers applicable to 'auto-- in connection with a relay system; as its application theretoisparticularly beneficial, although it is applicable to any system and at pre-digitand digit stages and pled in'a manner: similar t0" the outgoing.-

Specification Letters farm." P t t 1 157 29, 1919, Application medication 20,1917. sriaiiialsspa' had access to oiiecommon group of trunks,

only about 54 trunks would be required for a corresponding calling rate. *This invention approxlmate's to the latter condition'by a novel way of multipling the trunklines, and

at the sametimereduces the number'of-bank teI'IIllHiLlS" or relays necessary.

traflic i 'equirement's." I According to this invention" I multiple a group of trunks ovei' each incoming line of The number of terminalsor relays wlll vary according to 1000-lines{ihave access -totwo :or possibly threefsimilar trunks, but my'particular arrangement of"trunks reduces this-Tto the minimum; I The number'of trunks in each combination will depend upon the require rnentsfi 3 1 r My anvention so lmproves theaccess of incomlng lines to outgoing trunks, and so automatically and" efficiently distributes the traffic that secondary "pie-selectors are unnecessary,f"primarypre-selectors can be of smaller capacity than 'form'erly; no intermediatedistributing I board is necessary to equalize the trafiic, and the'numberof trunks in a group *can be increased to-meet traffic growth as required without interference with the existing'wiring. Adjacent" lines have access to different combinations of trunks, which :is particularly valuable-= on pricl atebranch exchange working.

calls, theiincomlng trunks being multi- The invention is alsozwapplicab'le to-the digit' 'stages'- Where preferably the incoming lines are divided into small sub groups having .access to difi'erent: conibinationsuof a group of outgoingilinesv ":1"

v:I'ido not limit my invention to the applications specified, as itzwill be-readily understood. that: it: is; applicable to any; I group of lines having access :to another group of lines in telephony, itelegraphy 10rany other art.

" In order that my invention. maybe the invention is also applicable to incommore readily understood I will now describe it Withreference to the accompanying illustrative'drawlngsand other features of my invention will be 'set outinthe claiming" clauses. U 7 Flgure 1 lllustrates its application when each incoming line has access to a plurality -,use of a small number of lines.

' wired to 7 Fig.2 shows its application to sub group s of incommg .lmes having access by l nks to av plurality of outgoing. lines.

Fig.- 3 shows its application to trunks,

]a cks on a manual telephone switch board.

Fig. 1 illustrates diagrammatically a 25- line switchboardwith subscribers lines 0 to 24, having access to a group of18 outgoing trunks, capable of being lncreased to 24 trunks. Such a number of trunks 1s-capable of serving a much larger number of sub scribers than that specified, but 25 are suflicient to illustrate the application of. the

invention.

The group of outgoing trunks isfdivided into 5sub-groups o and 41 I Sub-group 0 contains .7 trunks lNos. T1 to T7,, and these are multipliedfover .the subscribers" lines .as manytimes .as '2 goes into the total subscribers lines; It will thus beseen that the 7 trunks are multipliedover the subscribers lines 0 to 6 inclusive, then 7 to 13 inclusive, 14 to' 20. inclusive, and

soon. V 1

Sub-group 1'2 contains5 trunks,,l los; T8 to T12, and they are-multiplied in a similar manner so that the 5,:trunks. are repeated on subscribers lines 0 to 4 inclusive, 5. to 9 inclusive, 10 to- 14 inclusive and so on.

Sub-group '0 contains in the first instance 3 trunks, Nos. T13 to T15, multiplied in a similar manner.- Alternate sets of 3 sub- 'scribers lines are served by 'multiples'in separate cables, the two cables in the first finstancebeing connected by bridle wires (1., b, 0, so that they form-a complete m'ultiple of 3 trunks. 1 Y Sub-group 5 contains 2 trunks Nos. T16 andTlZ which arewired by 2 cables in the manner just described so that there is one complete multiple repeated for every -2.subscribers lines. I Sub-group '0 contains-one trnnkNo. T18 which is wired by 2 parallel cables as before, so that all the 25 subscribers lines have access to this one trunk.

scribers lines have access to a different comblnation of 5 outgoing trunks. The following schedule shows the trunks t whichthe first 10 subscribers lines have access:

' 25 subscribers lines to 18 trunks.

Line 0 has access to trunks 1, 8, 13, 16, 18. Line 1 has access to trunks 2, 9, 14, 1 7, 18. Line 2 has access to trunks 3, 10, 15, 16, 18. 1 Line 3 has accessto trunks 4, 11, 13, 17 18.

Line 4 has access to trunks 5, 12, 14, 16, 18.

Line.5 has access to trunks 6,8, 15, 17 18. Line6 has-access to trunks 7, 9,13, 16, 18.

Line 7 has access to trunks 1 10, 14, 17, 18. :Line 8 has access to'trunks 2, 11, 15, 16, 18.,

. Line 9 has access to trunks 3, 12', 13, 17, 18.

When, owing to increase of traffic or-toj meet .the requirements of additional lines added, it is necessary to increase the number 7 of trunks, this can be readily done without sub-gro p 11. are removed and trunks 22 and 23 added so that alternate pairs ofsub scribers lines have access, to different outgoingtrunksin this sub group. If three adliti'onal trunks are required, then the bridle wires a, b and c in sub-group o are removed and additional trunks 19,20 and 2 l 'arefiadded so that alternate subgroups of 3 subscribers have accessto different trunks. i n 1 5 If all the bridle wires a to f are removed and'new trunks added as described, their thej18 trunk linesof the original equipment areincreased to 24. p These figures are given merely-by way of example, and the access of the first 10 subscribers lines with 24 trunks is shown in the following schedule "25 .s zb bsc'r'ibc'rs to 24 tmmks.

Line Oohas access to trunks 1, v8, 13, 16, 18. i

, Line 3 has access to trunks, 4, 11,19, 23,, 24. V

Line'4 has access to trunks 5, 12,20, 16, 18. Line 5 has access to trunks 6, 8, 21,17, ,Line 6 has access to trunks 7, 9, 13, 22, 18. 'Line 7rha's access to trunks 1, 10, 14, 23, 24.

Line 8 has access to trunks 2, 11, 15, 16,18. Line 9 has access'to trunks 3, 12,19, 17, 24.

Fig. 1 shows, a similar arrangementapplied to a larger equipment, for example,

1000 subscribers lines having access to 60 trunks in the first instance,- t-he trunks being capable of increase to 86. The intersections of lines'at the points '5} indicate relay contacts which correspond to the contacts 7' in Fig. l.

Each sub-group" of outgoing "j unctions is indicated by" a line representing'af cable to avoid confusionowing to the greater-num berof lines-f e h p.

In 1 the "horizontalf-liiies S numbered to carry the trafiic ironi the 1000 incoming lines, but 7 anyoth'er frequisi-teaotal may be used. The groiifl'of trunksis divided into sub' groups] *0 according ="the acc'ess' req iredfa di? fi eia ei hOW i y-- W y O X- combination of'trunksi' A diflerent number of trunks; is preferably allotted to each subgroup; i'and jpre'ferably suchiiu'riibeifl S pr me-, One'exce'ption to 1 this" is 's'hown,"fthe :numberIof "trunks in the five sub-group's being 17, 12, 13, 11, 5,- total each d" t lte na e multiples, the two cables being connectedin "parallel, at a joint board to 11' trunIrs QSub-grou ,5 is shown wired by fourcables e, f, 4 different multiples of f 4 sections "These are all I connected in] parallel she-jams *board The other, sub-groupsare'wire'd by singlemultiplied-cables. the sub-group of.

. me trafi i cr sa 5 may be in'creas to 10--"by""breaking the bridle, wires 0; c and connecting a, g,

d. f we t f bls$ insets 9 Pair -1- Paral l i ilv 'f a tern mu pl byftrunks c' g'g The trunk multiple nunv by .16, the" two cables of sub-group 11 are p r e a d'., $1Tl l e nected to the} separated cable-mthus increasing-the multiple capacity to 22: The trunk multiple numbers -45 155 ohcablejn will thus be repla ced by numbers 76 -861 7 The right hand] sub-group I, should "then; be" 1 reduced again to?! with & cables-in parallel" Toin crease further by 5,' openj ;out*again the 5 subgroup 'toftwo pairs 1 of cables ,-in parallel.

To increase furtheI'. -'b'y -10,- open out the 5 (10) sub group,' andincrease the trunks in. that SubTgrOupfto, 20 'connect'in'g trunks f and h, Theftrunlr" multiple "of cable 6 will then be numbers-56 60, cable'fnumbers 61-65, cable g numbers86+70 and cable-h numbers 71 -75, Thefgroup' has thus been increased froni 60 by 5, '6, 5, 10, to" a total of 86" trunks without interferin with the .e Ti ings The incoming; iinesfina be worked in, one grou up to 10,000 ;l1nes,qthe increase in num er always'bringing aboutincreased v -It is 'assumed that 60 outgoingtrunksfare sufficient g", h, each serving efiiciency and a percentage decrease in the number of outgoing trunks owing to the efficiency .of largegroups. 1 I

In such larger groups :a decrease in vthe number of incoming lines having access to a plurality of similar. outgoing lines occurs, until at a certain point no access to a similar plurality exists. 7

By way of example, to increase to 2000 lines or over all sub-groups would be wired by a plurality of cables; with the following result For 1000.lines,17, 14, 13, 11, 5:60 outoing trunks.

For'2000. lines .34, 28, 26,22, 10:120 outgoing trunks.

-For traffic ::growth 44,- 202158 outgoing trunks. I

The diflerent sub-groups are doubled as required, and the ultimate; ,may be utilized for a 3000v line group at onecalling rate,

and for 2000slines-on a higher calling rate.

It :will be found that theincoming line having. a number which corresponds with the product of anyq-two sub-group numbers will have access to two trunks in common with one ormorexotherv lines; for example, in a 60'trunkgroup,.subscriber 55 (11x5) will have access totrunks in sub-groups 11 and 5 incommon'with No. 0 and every multipleof 55, and subscriber 238 (17x14) will have access toa 17 and 14 sub-group in common with No.0 and multiples of 238. At the product of any 3/ sub-group numbers an incoming line will have access to three trunks similar'to No. 0; for example, Nos. 0 and 715i ('13x11x5) have access to- .the' same trunks in sub-groups; 13, 11 and 5; sub 0 .have access to three simiscribers 0 and 7 lat trunks in 14, 11 and5; and 0 and 910 accessto3 similar trunks in 14, 13- and 5. Other multiples and combinations are be yond the l000 line multiple, and there are never more than two subscribers havin access to the same three trunks in a com ination, and no two subscribers have access to the sametrunks in the 17 and 1 1 groups.

'It will be obvious from the. mathematical formula for the number of combinations of nthmgs 1* at a time, that as the number of trunksincreases, this common access is decreased, until in thedexample of a'10,000 line exchange'with 597 trunksas described below there would be no common access to a plurality of similar outgoing trunks.

" 'A 2000 line pre-selector unit having 107 trunks can be increased to 5000 (or other number according to the traffic) with 262 trunks:

Original equipment 2000 lines having access to 31, 29, 23,13, 11:107.

Increased to 5000 lines having access to 62,58, 46, 26, 22:214.

Allowance for lncreased traflic growth 52,

it is sometimes advantageous to reverse the trunks 0r otherwlse to transpose them so- 7 that the trunks of a sub-groupare'in a-different order in the repetitions of the multiple. Also in some c rcumstances 1t isadvantageous to repeat the same trunks inwav plurality of sub-groups or levels.. pForeX- ample, in a group of 60 trunks divided into 5 sub-groups, -trunks may be multipled as a fir'st sub-group or level, 31 (Nos. 5 to' 35) multipled as a second level, 36-to 4:4: plus 1' to t, total-,13, multipled*as a. third level, 11 and 5 as fourth and fifth. levels (arranged as before for'increasing thetotal lines in group), total 60. 'If-a greater in? crease is required than can be glven 1n the last two levels, new trunks canreplace 1 to 4 on the thirdlevel, and a new set of trunks replace5 to '35 on the second level. 1

The arrangement has been described for adjacent "indlvidual incoming lines having. access to different trunks, butwwhen tralfic 1s light and for small exchanges ap-lurality of adjacent incoming lines may have access to.

the same trunks and combinations of this arrangement may be used. For eizample,.ad-

jacent indlvldual lncoming lmes may each have access to a different trunk on the first sub-group or outgoing trunks, pairs of adjacent incoming lines may have access to each outgoing trunk of the second subgroup, three adjacent incoming lines may have access to the same outgoing trunk-of thethird sub-group, and so on, the outgoing sub-groups of 'outgoing trunks being multipled as before described.

7 Fig. 2 shows invention adapted to work with incoming lines IL, which may be subscribers or trunk lines, arranged in small sub-groups which connect with the trunks by links LK, and usedat a pre-selecto-r or at'a digit switching stage. Three incoming lines are shown connecting by wipers, relays and'the like to 5 or other number of links LK, which in'turn connect by similar 7 means with a set of 5 (one in each subgroup c wa or other number of ojutgo For very small'groups of incoming lines without affecting be provided. with the usual connecting means to extend one of agroup of calling llnes to a trunk llne. I

I have shown the division of subgroups as first choicelines and the smaller as subsequent and final choice lines. Imay, however, especially inv semi-automatic sys} tems and to obtain concentration oi traffic,

reverse this arrangement, making the 'small-" dr the larger sub est sub-group first vchoice an groups subsequent cl 'o ceflinesi V What I claim 1s:H v

The combinationfof aigroup of lines and a;sn1aller group of to'whichthe' first lines have access and which isdivided' into sub-groups, the'numberf off sub-groups numberoflines. o v

'2. The combination of [a group of lines and a smaller group dilines to which the first lines have access and which is divided into sub-groups, the number wolf subgroups being equal 'to the number of linesto which each line ofthe first group is to. have ac cess and eachjof plura ity of sub-groupscontaining a. diflerent number of lines,

.3. The combination of a, group of lines and a smallergroup of lines to which the first lines, have access and' which is divided into sub-groups so that the number oflines in asub-group; can be increased in number without afi'ecting the of; the s'ub g 11'ps I 45. The combination of a' group of lines and asmaller group of linestowhich the first lines have access and Which is divided into sub-groups, the number ofjsub groups being equalto the number ofclines to Which each line of the first group is tohave access, each sub-group containing a difierentnuim ber of lincsand the lines of each sub-group being multipled as many times as the number of lines of such sub-group goes into the number of lines of the first group.

5, The combination of a group of lines and a smaller group of lines towhichthe first lines. have access and which is divided into sub-groups, the number of sub-group's being equalto thenumber 10f lines to which each line of the first group is to have access, each of a plurality of sub-groups containing a different number or, lines and the lines of each sub-group being multipled" as many times as the number of lines of such'subgroup goes-into the number of lines of the first'fll'oupe w v V 1 .c 6. The combination of agroupof lines and a smaller group of lines, to which the first lines have: access 1 and Y which is divided into sub-groups so that the number of lines in a subgroup can beincrea'sed in number '-'the wiring ofthe sub iich the lines of each sub vgroup ,andin w 7 the number of lines of the firstv group. 1

a 7. The combination of a group of lines and a smaller group of lines to which the first lines have access "and which is; divided into sub-groups, the number of sub-groups being equal to the number of lines to which eachline of the first group is to have access, each sub-group conta1n1ng a different num-j ber of lines and the lines of a sub-group be-' ing multipled as many times as the numberbercf lines ofthe first group. 1

8. The combination of a groupof" lines and a smaller group of lines to which the of lines of that sub-group goes into thenumfirst lines have access and which is divided into sub-groups, the number of subgroups being equal to the number of lines to which each line of the first group is to have access,

each of a plurality of sub-groups containing a different number of lines and the lines of a sub-group being multipled as many times as the number of lines of that sub-group goes into the number of lines of the first group.

9. The combination of a group of lines and a smaller group of lines to which the first lines have access and which is divided into sub-groups so that the number of lines in a sub-group can be increased in number without affecting the wiring of a sub-group and in which the lines of a sub-group are multipled as many times as the number of linesof that sub-group goes into the number of lines of the first group.

10. The combinatlon of a group of lines and a smaller group of lines to which the first lines have access and which is divided into sub-groups, the number of sub-groups being equal to the number of lines to which each line of the first group is to have access, the lines of each sub-group being multipled as many times as the number of lines of such sub-group goes into the number of lines of the first group and the lines of a sub-group being in difierent numerical orders in the repetitions of the multiple.

11. The combination of a. group of lines and a smaller group of lines to which the first lines have access and which is divided into sub-groups, the number of sub-groups being equal to the number of lines to which each line of the first group is to have access, the lines of each sub-group being multipled as many times as the number of lines of such sub-group goes into the number of lines of the first group and the lines of a sub-group starting from a different numerical base in repetitions of the multiple.

12. The combination of a group of lines and a smaller group of lines to which the first lines have access and which is divided into sub-groups, the number of sub-groups being equal to the number of lines to which each line of the first group is to have access,the lines of a sub-group being multipled as many times as the number of lines ,ofthat sub-group goes into the numberof orders in the repetitions of the multiple.

13. Thecombination of a group of lines and a smaller group of linesto which the first lines have access and which is divided. into sub-groups, the number of sub-group's" .being equal to the number of lines to which is to have access,

each line of the first grou eing multipled as the lines of a sub-group many times as the number of lines of that sub-group goes into the number of lines of the firstgroup and the lines of a sub-group starting from a diiierent numerical base in repetitions of the multiple.

14. The combination of a group of lines and a smaller group of lines to which the first lines have access and which is divided into sub-groups, the number of sub-groups being equal to the number of lines to which each line of the first group is to have access, the lines of each sub-group being multipled as many times as the number of lines of such sub-group goes into the number of lines of the first group and the number of sub-groups of incoming lines having access to subgroups of outgoing lines varying in different sub-groups of outgoing lines.

15. The combination of a group of lines and a smaller group of lines to which the first lines have access and which is divided into sub-groups so that the number of lines in a sub-group can be increased in number without afiecting the wiring of the subgroup, one of the sub-groups having its multiple wired by a plurality of cables.

16. The combination of a group of lines, a smaller group of lines to which the first lines have access and which is divided into sub-groups, the number of sub-groups being equal to the number of lines to which each line of the first group is to have access, a group of trunk lines and a plurality of cables serving the multiple of a sub-grou and connected in parallel to a group of trun r lines equaling in number the circuits in one cable.

17. The combination of a group of lines, a smaller group of lines to which the first lines have access and which is divided into subgroups, the number of sub-groups being equal to the number of lines to which each line of the first group is to have access, a group of trunk lines and a plurality of cables serving the multiples of a plurality of sub-groups and each connected in parallel to a group of trunk lines equaling in number the circuits in one cable.

18. The combination of a group of incoming lines and a group of outgoing trunk lines, each incoming line having access to a different combination of outgoing trunks,

and nevermore than tWo incoming lines having access to the same three trunks of the and no incoming line having access to more than tWo hnes in common W1th other line's.

20. The combination of a group of incoming lines and a group otoutgoing trunk lines, each lncoming line having access to a different combination of outgoing trunks,

lines andfwhich are divided into sets, each set having accessto a different combination of outgoing lines, V V

In testimony-that I claim the foregoing as my invention, I have signed my name this 28thday'ofFeb1 uary1917. 7

i -WILLIAM AITKEN.

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